Hot-gas reciprocating engine in which a plurality of closed thermodynamic cycles are performed simultaneously and which includes a compressor means



& June 30, 1953 A. A. DRos 2,643,

HOT-GAS RECIPROCATING ENGINE IN WHICH A PLURALITY OF CLOSED THERMODYNAMIC CYCLES ARE PERFORMED SIMULTANEOUSLY AND WHICH INCLUDES A COMPRESSOR MEANS Filed Nov. 17, 1949 r40 "4: new ma" arrow INVENTOR ALBERT AUGUST DROS Patented June 30, 1 95 3 OFFICE HOT-GAS RECIPROCATING ENGINE IN WHICH A PLURALITY OF CLOSED THERMODYNAMIC CYCLES ARE PER- FORMED WHICH INCLUDES MEANS SIMULTANEOUSLY A N D A COMPRESSOR Albert August Dros, Eindhoven, Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Cnn., as trustee Application November 17, 1949, Serial No. 127,918 In the Netherlands December 30, 1948 3 Claims.

Hot-gas reciprocating engines in which a plurality Of closed thermodynamic cycles are performed simultaneously and in which all pistons are constructed to be double-acting are known. The operation of these engines is such that both surfaces of a piston co-operate to produce the variations in volume of spaces in which the cycles are performed. As a rule,.it is desirable that such engines should be so constructed that the communication channels between the cylinders have the same length so that the volume of the space in which a cycle is performed is the same for all cycles. In this case, a determined arrangement of the cylinders is required, for. example, the centre lines of which may be located on a circle or at the corners of a parallelogram.

The object of the invention is to permit greater freedom in the positioning of the cylinders in such a hot-gas engine.

According to the invention, a hot-gas reciprocating engine in which a plurality of closed thermodynamic cycles are performed simultaneously, comprises two cylinders in each of which a piston moves of which only one of the two surfaces co-operates to produce variations in volume of a space in which a cycle of the hot-gas reciprocating engine is performed, whilst in each of the other cylinders a piston moves of which both surwith a heater 1, a regenerator 8 and a cooler 9. The heaters and coolers are externally heated and cooled with the use of external fins II] and II, respectively. lhe cylinder I, which may otherwise be exactly similar to each of the cylinders 2 to 6, however, is not provided with a heater, a regenerator and/or a cooler. Identical pistons l2a, b, c, d, e move in the cylinders 2 to 6,

faces co-operate to produce variations in volume of spaces in which cycles of the hot-gas reciprocating engine are performed.

In an embodiment of the invention, the hotgas reciprocating engine is so constructed that the cylinders are arranged in a straight line and in each of the first and the last cylinders a piston is movable of which only one surface co-operates to produce variations in volume of a space in which a cycle of the hot-gas reciprocating engine is performed. In this case, it may be advantageous if of one or more of the pistons of which only one surface co-operates to produce variations in volume of a space in which a cycle of the hot-gas reciprocating engine is performed, the other piston surface constitutes the compressing member of a compressor.

The term hot-gas engine is to be understood to include a refrigerator or a heat pump operating according to the reversed hot-gas engine principle.

The invention will now be explained more fully by reference to the accompanying drawing, showing, by way of example, one embodiment thereof.

A hot-gas reciprocating engine comprises cylinders l, 2, 3, 4, 5 and 6 of which the cylinders 2 to 6 are identical and are each provided respectively. A piston 13, which moves in the cylinder l, is different from, but may have a shape similar to that of the pistons l2. Each piston is connected by means of a piston rod and a driving rod M to a common crank shaft l5, of which the cranks are at an angle with one another such that the phase difference between the movements of the pistons I242, b, c, d, e and I3 required for the operation of the hot-gas reciprocating engine is obtained. The space Ita above the piston l2a and the space 20a below the piston [3 which communicates therewith through a channel [9a constitute a space in which one cycle of the hot-gas reciprocating engine is performed, the volume of this space being determined by the upper surface of piston 12a and the lower surface of piston [3. Similarly, the space 16b in cylinder 3 and the space 2% under the piston 12a which communicates therewith through a channel [9b are determined by the upper surface of piston I2b and the lower surface of piston 12a. The conditions are similar for the spaces 20c, 20d, 20c and the spaces Sc, :1, 6, etc. of the other cylinders co-operate due to the movements of the pistons I2b, 12c, [2d to produce the volume variations of other cycles performed simultaneously in the hot-gas reciprocating engine. However, only the upper surface of piston 12c and only the lower surface of piston I3 co-operate to this effect. The cylinder l comprises a communication channel I! communicating with the space above piston l3 and the cylinder 6 comprises a communication channel I8 communicating with the space below piston l2e. The two channels l8 and I! may be connected to valves Ila and l8a and a receptacle 2L The upper surface of piston [3 and/or the lower surface of piston [22 constitute the compressing members of compressors capable of compressing, for example, combustion air to be supplied through outlet valve 22 to gas burners for heating the hot ends of the cylinders or the regulating gas required for the operation of the hot-gas reciprocating engine. Alternatively, it is possible to utilise one or both piston surfaces for other purposes not directly connected with the operation of the hot-gas reciprocating engine, for example, for pumping water.

The important advantage is afforded that the advantages of a double-acting hot-gas reciprocating engine in which the communication chan nels between the spaces have the same length and hence the clearance space of each cycle is the same are obtained, while, nevertheless, the cylinders are arranged in one line. Furthermore, the use of the invention permits of a much wider choice of the phase difference angle between the movements of each two co-operating piston surfaces than is the case with a double-acting hotgas reciprocating engine of conventional construction. Furthermore, the cylinders may be positioned relatively to one another with a greater freedom of choice, for example in the best manner in' view of the space available therefor.

Alternative arrangement are possible within the scope of the invention, for example two such engines may be placed side by side to operate on a common crank-shaft. In this case the cylinder I and/or the cylinder 6 may be common to the two engines.

What I claim is:

1. A hot-gas reciprocating engine in which a plurality of closed thermodynamic cycles are performed simultaneously, comprising a plurality of cylinders, all but one of said cylinders having a heater, a regenerator and a cooler, a piston in each of said cylinders having two surfaces and dividing each of said cylinders into two spaces, the movement of each piston surface producing volume variation of each adjacent space, a space n of one cylinder cooperating with a space of another cylinder in each thermodynamic cycle, the first and the last of said cylinders each only having one space in operative connection with a space of another cylinder, the other of said spaces in said first and last cylinders constituting a compression space in which one surface of the piston therein acts as the compressing member, and the remaining cylinders having each of their two spaces in operative connection with a space of another cylinder.

2. A hot-gas reciprocating engine in which a plurality of closed thermodynamic cycles are performed simultaneously, comprising a plurality of cylinders arranged in a straight line, a piston in each of said cylinders having two surfaces and dividing each of said cylinders into two spaces, the movement of each piston producing volume variation of each space, a space of onecylinder cooperating with a space of another cylinder in each thermodynamic cycle, the first and the last of said cylinders each only having one space in operative connection with a space of another cylinder, the other of said spaces in said first and last cylinders constituting a compression space in which one surface of the pistons therein acts as the compressing member, and the remaining cylinders having each of their two spaces in operative connection with a space of another cylinder.

3. A hot-gas reciprocating engine in which a plurality of closed thermodynamic cycles are performed simultaneously, comprising a plurality of cylinders, all but one of said cylinders having a heater, a regenerator, and a cooler, external fins mounted on each of said heaters and coolers for heating and cooling said heaters and coolers, respectively, a piston in each of said cylinders having two surfaces and dividing each of said cylinders into two spaces, the movement of each piston surface producing volum variation of each adjacent space, a space of one cylinder cooperating with a space of another cylinder in each thermo dynamic cycle, the first and the last of said cylinders each only having one space in operative connection with a space of another cylinder, the other of said spaces in said first and last cylinders constituting a compression space in which one surface of the pistons therein acts as a compressing member, and the remaining cylinders having each of their two spaces in operative connection with a space of another cylinder.

ALBERT AUGUST DROS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 991,989 Holm May 9, 1911 1,603,779 Koenig Oct. 19, 1926 1,760,415 Koenig May 27, 1930 2,067,453 Lee Jan. 12, 1937 2,272,925 Smith Feb. 10, 1942 2,480,525 Van Weenen Aug. 20, 1949 2,486,081 Van Weenen Oct. 25, 1949 

